This invention relates to electrical connector assemblies and, more particularly, to electrical connector assemblies of densely packed contact members capable of passing fast rise time pulses without cross-talk between adjacent contact members.
There presently exists in the marketplace a large family of electrical connectors which have a thick plastic housing and long channels, or holes, into which either male or female contact members are inserted. These connectors are typically utilized for mounting and connecting daughter printed circuit boards onto mother printed circuit boards and represent a major multi-million dollar investment in tooling for the housings, the contact members and the assembly machinery. In general, when signals passed by the connector assembly have two nanosecond or slower rise times, these connector assemblies have proven to provide satisfactory performance. However, the industry is moving to much faster rise times and, with the shortening of the rise times this tends to increase the cross-talk between adjacent contact members. In the past, to eliminate such cross-talk, signal-carrying contact members have been surrounded by between four and eight grounded contact members which act as a shield. A major problem with this approach is that as the complexity of the electronics mounted to the printed circuit board increases, there is insufficient room for the extra grounded contact members. Accordingly, it is an object of the present invention to provide an electrical connector assembly which eliminates cross-talk between signal-carrying contact members without the use of grounded shielding contact members.
One approach to solving this problem is detailed in my U.S. Pat. No. 4,906,194, where I disclose a high density connector assembly for an integrated circuit chip carrier which includes a stack of metallic plates having apertures which form chambers for holding contact members therein. The stack of plates provides a ground shield around each of the contact members to prevent cross-talk therebetween. To insulate the plates from the contact members, the plates are coated with an insulating layer of dielectric material. This method of constructing a connector housing block, while suitable for relatively thin connectors of the type disclosed in the referenced patent, is economically prohibitive for larger circuit board to circuit board connectors which frequently have a thickness greater than one-half inch.
It is therefore a further object of the present invention to provide a larger size connector assembly which provides cross-talk shielding and which salvages as much as possible the tooling, assembly machines, etc., which already exist for the present connector assembly which it replaces.